The present invention relates generally to leveling devices, and more particularly, to an accelerometer augmented leveling device.
It is well known that aerospace systems, such as missile systems, require internal control systems for the purpose of maintaining a particular level or attitude with respect to a fixed frame, such as the earth.
Currently, spirit levels or bubble level devices are used in conjunction with missile navigation systems to maintain a particular attitude of an object prior to launch or during flight thereof.
Typical spirit levels include a closed glass tube (vial) having a circular cross section and a center line also defining a circular arc. The internal surface thereof is filled with ether or low viscosity liquid with enough free space remaining for the formation of a bubble of air and other gasses.
Spirit levels are, however, subject to condensation and fluid breakdown over time, resulting in loss of efficiency and accuracy.
As was mentioned, this type of leveling device is used in aerospace or in a portion of aircraft or spacecraft navigation or guidance systems. During operation of those system types, the temperature in the operating environment of the spirit level changes over a wide range. Consequently, leveling must be measured and controlled with a high accuracy over a wide range of temperatures and temperature gradients. This is often a difficult and inefficient process.
The disadvantages associated with current leveling systems have made it apparent that a new leveling system is needed. The new leveling system should eliminate fluid breakdown, substantially minimize temperature sensing requirements, and should also improve leveling detection accuracy. The present invention is directed to these ends.
In accordance with one aspect of the present invention, a leveling device includes a platform defining an xz-plane. A first dual bridge sensor is coupled to the platform at an angle such that the first dual bridge sensor is sensitive to movement of the first dual bridge sensor in an xy-plane. The first dual bridge sensor comprises a first flexure plate generating a first dual bridge sensor signal in response to movement of the first flexure plate. A second dual bridge sensor is coupled to the platform at an angle such that the second dual bridge sensor is sensitive to movement of the second dual bridge sensor in the xy-plane. The second dual bridge sensor comprises a second flexure plate generating a second dual bridge sensor signal in response to movement of the second flexure plate. A processor drives the first dual bridge sensor and the second dual bridge sensor with a precision sine wave.
In accordance with another aspect of the present invention, a method for operating a leveling system includes driving a first flexure plate dual bridge sensor with a first precision sine wave and generating a first dual bridge sensor signal from the first flexure plate dual bridge sensor. The method further includes driving a second flexure plate dual bridge sensor with a second precision sine wave and generating a second dual bridge sensor signal from the second flexure plate dual bridge sensor. A platform rotates clockwise when the first dual bridge sensor signal is greater than the second dual bridge sensor signal. The platform rotates counter-clockwise when the second dual bridge sensor signal is greater than the first dual bridge sensor signal. The method still further includes driving a third flexure plate dual bridge sensor with a third precision sine wave and generating a third dual bridge sensor signal from the third flexure plate dual bridge sensor. The method further includes driving a fourth flexure plate dual bridge sensor with a fourth precision sine wave and generating a fourth dual bridge sensor signal from the fourth flexure plate dual bridge sensor. The platform rotates clockwise when the third dual bridge sensor signal is greater than the fourth dual bridge sensor signal and rotated counter-clockwise when the fourth dual bridge sensor signal is greater than the third dual bridge sensor signal.
One advantage of the present invention is that it generates a dynamic range and granularity sufficient for InterContinental Ballistic Missile (ICBM) usage. Additional advantages include that the leveling device consumes less power than prior leveling devices, while dramatically improving reliability and reduction in manufacturing costs.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.